Interception of a call being communicated between two telephone subscribers may become necessary for many different reasons. One reason for interception of a call is for the enforcement of the law by the agencies authorized to intercept private communication calls. For the obvious reasons, such interception should be made unobtrusively to maintain its secrecy. To maintain secrecy, the authorized law enforcement agency may establish a monitoring station at a convenient location to unobtrusively intercept call connections originated or terminated at a subscriber. In case of terrestrial communication systems, such as land based telephone systems or cellular phone communication systems, the monitoring station may be setup at a public switched telephone network (PSTN) near the location of the subscriber, or in case of cellular communication system, the monitoring station may be setup at a mobile switching controller (MSC). Therefore, interception of such a call connection can conveniently be accomplished.
In case of satellite communication systems, however, a call connection originated from a subscriber may not pass through PSTN or MSC because a satellite subscriber (SU) is capable of directly carrying a call connection with a satellite or another SU through a network of satellites without going through a PSTN or MSC. Similarly, a satellite subscriber is capable of receiving a call connection directly from a satellite while all ground connections are cut-away. As a result, two SU's may have an ongoing communication call directly by making a series of call connections through a network of satellites without maintaining any ground connection. Since there may not be any ground connections, interception of a call connection originated or terminated at a SU in a satellite communication system has become difficult and in some instances impossible.
Therefore, there is a need for a method for unobtrusively intercepting communication calls in a satellite communication system.